Not charging & charger not unlocking

[Shengis]

So after 4 months of reasonably happy driving with the MG4, what I feared might happen has happened.

Went into my garage this morning, it hadn’t charged overnight and the cable was stuck locked in the charging port. None of the usual lights round the charger like the car wasn’t recognising it.

Had to emergency release the cable and drive to work. Showed fault with 12v battery pinging at me every few seconds. Now I have just enough miles of charge left to take it to the garage so I’ll have to phone tomorrow.

Nightmare

 

[Jomarkh]

Have you tried disconnecting the 12V battery for ten minutes?

 

[Shengis]

Have you tried disconnecting the 12V battery for ten minutes?

No, is that a possible fix?

 

[the briggie]

I would ask why the 12v was alerting in the first place? Has that alert stopped?

Most times when the 12v goes low the car is effectively dead...could it have went into some kind of saver mode to stop any drain, that would stop charging potentially, and maybe the cable lock issue. You could start the car which in turn should charge up the 12v battery and stop the alerts...all theory no hard facts, just putting it out there

P.s if it had not started charging the 12v would not be " topped up" perhaps


Intelligent Charging
The 12V battery SOC (State Of Charge) is constantly
monitored, when the vehicle is power OFF it is possible,
under certain conditions, that the HV battery will
automatically charge the 12V battery to ensure the
vehicle starts. This function will activate and switch off
automatically.
Note: The system will suspend intelligent charging if a
fault is present, when starting or the vehicle is being
charged by an external device.
Note: The driving range will be reduced after
intelligent charging.
Note: The intelligent charging function is suspended
when the high voltage battery is in a low SOC.


The more I think about this...it did not charge, the charger was retaining the cable lock, the car opened....which should have allowed cable disconnect, the car started, 12v battery alerts appeared. Could it be a charging station error that was signalling with the car, keeping relays active which would draw on the 12v battery? Just pontificating out loud

 

[Ian Key]

Was the car left unlocked in your garage which could explain why the charge didn't start and because the car was in a state of readiness it drained the 12v battery?

 

[Shengis]

This is an interesting one. So I got the AA out and he simply charged the 12V battery at which the car sprung back into life. Lots of errors with the battery being flat so I took it out for a drive and all errors have now disappeared. I went to see if it would charge and the lights round the charging port we’re back and it’s now charging fine.

So I’ve concluded that it didn’t charge or release the cable because for some reason the 12V battery was drained. Was it because I forgot to lock the car so it was on standby mode for hours? Maybe, however the AA guy told me to leave the car in standby mode for 20-30 minutes to charge the battery so which is it? How and when does the 12V better get charged?

Anyway I’m giving it a chance over the weekend and see if I have any more issues instead of taking it into the MG garage….

 

[the briggie]

I have a monitor on my current EV 12v battery
12v charges;
When HV charging is active
When in ready to start driving/driving

Can someone confirm MG4 is the same?

 

[siteguru]

Yes it is.

 

[Shengis]

I have a monitor on my current EV 12v battery
12v charges;
When HV charging is active
When in ready to start driving/driving

Can someone confirm MG4 is the same?

Does this mean there is somewhere to view to state of charge of the 12v battery? I wasn’t aware of this problem until an error message appeared.

So I was going to drive the car today but I’ve got an email from the AA starting it needs to be checked by the dealer prior to carrying on driving it at otherwise, if it breaks down they may refuse to assist. So I’ll need to call the dealer and get it booked in for Monday.

Totally scunnered (peed off for the non-Scots!) with all this hassle. I’ve ignored all the other annoying things wrong with this car, telling myself it’s fine but I’m really losing patience with it now.

 

[tsedge]

Does this mean there is somewhere to view to state of charge of the 12v battery? I wasn’t aware of this problem until an error message appeared.

So I was going to drive the car today but I’ve got an email from the AA starting it needs to be checked by the dealer prior to carrying on driving it at otherwise, if it breaks down they may refuse to assist. So I’ll need to call the dealer and get it booked in for Monday.

Totally scunnered (peed off for the non-Scots!) with all this hassle. I’ve ignored all the other annoying things wrong with this car, telling myself it’s fine but I’m really losing patience with it now.

The MG app shows the current 12v battery voltage.

 

[Ayoull]

Towards bottom of the vehicle status screen

 

[Macadoodle]

I have a monitor on my current EV 12v battery
12v charges;
When HV charging is active
When in ready to start driving/driving

Can someone confirm MG4 is the same?

But your last post states that the car can also close the contactors of the main battery on the fly to enable charging of the 12v if needed ?
Cool feature if it works, our leaf was a fekker for leaving you stranded on the driveway on a winter morning because the 12v went flat.

 

[Ayoull]

But your last post states that the car can also close the contactors of the main battery on the fly to enable charging of the 12v if needed ?
Cool feature if it works, our leaf was a fekker for leaving you stranded on the driveway on a winter morning because the 12v went flat.

Only works if the HV pack isn't at a low SoC as the car will sacrifice the LV battery to ensure the HV battery remains healthy

 

[the briggie]

As a matter of interest does the app show it raised during hv charging?

Macadoodle, yip my mind was on normal day to day charging but intelligent charging, with the caveats as stated, should kick in to top it up

Ayoull, be interesting to understand the SOC parameters to enable intelligent charging.

 

[Ayoull]

As a matter if interest does the app show it raised during hv charging?

Macadoodle, yip my mind was on normal day to day charging but intelligent charging, with the caveats as stated, should kick in to top it up

I've never really checked while it's charging before, I know while the HV battery is pulled in it floats at 13.2 - 13.9v

 

[Macadoodle]

Only works if the HV pack isn't at a low SoC as the car will sacrifice the LV battery to ensure the HV battery remains healthy

12v can only absorb a few hundred watt hrs so I would think the traction battery should be capable down to single digit %
Knowing MG's software though, it probably has to be above 80 or something

 

[Ayoull]

12v can only absorb a few hundred watt hrs so I would think the traction battery should be capable down to single digit %
Knowing MG's software though, it probably has to be above 80 or something

The BMS views a low SoC as 20% or less, as on the NMC packs below this voltage battery cell degredation is accelerated.

 

[Tight Git]

As a matter if interest does the app show it raised during hv charging

This is mine which is currently charging

 

[Macadoodle]

The BMS views a low SoC as 20% or less, as on the NMC packs below this voltage battery cell degredation is accelerated.

That's likely the cut off with the bigger pack if they've used common sense I guess.
Quite happy if they've pushed the LFP lower, I've about 500 WHr per % so not bothered about losing 1 % if it means I can leave the jumper cables in the case on a January morn.

 

[tsedge]

I've never really checked while it's charging before, I know while the HV battery is pulled in it floats at 13.2 - 13.9v

I see 12.3-12.7v when the HV is off and 13.5-13.8v when it is on, not checked when charging the car.